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4Matic (stylized as ''4MATIC'') is the marketing name of an AWD four-wheel drive system developed by Mercedes-Benz. It is designed to increase traction in slippery conditions. The four-wheel-drive system was developed in conjunction with Steyr-Daimler-Puch (now Magna Steyr), who manufactured the Mercedes-Benz G-Class in Austria. Almost all Mercedes-Benz vehicles featuring this system have an automatic transmission as standard equipment; the name is derived from 4-wheel drive and automatic. The first design of 4Matic system was introduced in 1987 on the W124 series (E Class) saloons (four-door) and estate (station wagon) cars. It was available with the 2.6 L and 3.0 L 6-cylinder petrol (gasoline) and diesel engines. Some newer versions of 4Matic are true AWD as the system remains active at all times.〔"Mercedes launches all-wheel-drive CL 500 4Matic" Left Lane. 27 February 2008, 9:40 AM ()〕 Sophisticated engine management and ABS systems control the amount of torque transferred to each wheel allowing the system to be effective at any speed. The first generation 4Matic system was originally a complex electronically controlled system with automatically engaging four-wheel drive (4WD), the system employs locking central and rear differentials to provide additional traction in slippery conditions. The centre differential, also known as the transfer case, contains two clutches. Each hydraulically enabled clutch is controlled separately to allow for three modes of operation: 2WD (mode 0) where 100% of available torque is available to the rear axle while the front axle is disconnected, and two 4WD modes which allow for 35/65 front/rear axle torque split (mode 1) or 50/50 front/rear axle torque split (mode 2). The rear differential lock, previously known as ASD on Mercedes-Benz models, can also be locked (mode 3) if rear wheel slip is still present when the transfer case 50/50 4WD mode 2 is engaged. Due to safety and stability concerns there is no front differential lock. The 4Matic system uses inputs from the three channel ABS system and a steering wheel angle sensor to decide when to intervene. 4WD is disengaged automatically if the ABS service brakes are applied. Engine throttle control is not inherent in the W124 system. Two W124 variants of the 4Matic system were produced: the first system (1986–1991) used a mechanical pressure test lever to disable the system hydraulically while the second system variant (1992/1993) used an electrical test switch to break power to the system. The later system variant when in test mode allows for continued operation of the rear shock self-levelling system (SLS) when installed. Plagued with reliability problems at first, the multi-plate clutch central differentials were prone to failure; it was withdrawn in 1993.〔Ritter, S. Problems Section. Mercedes-Benz E-Class Owners Bible 1986–1995. Bentley Publishers, 2007. ISBN 0-8376-0230-0.〕 The second generation of 4Matic was re-introduced on the W210 series in 1998/1999. Available only in left hand drive the cars were again manufactured at the Magna-Steyr plant in Austria. The second generation of 4Matic used a full-time 4-wheel-drive system with three open differentials front, centre and rear. Traction control is achieved using ETS (Electronic Traction System). This employs the ABS system with additional valves to monitor and then partially brakes any wheel which loses traction. This much simpler system is also used in the Mercedes-Benz M-Class SUV. The second and third generation 4Matic systems are currently available on the A-Class, B-Class, C-Class, E-Class, G-Class, S-Class (and former CL), GLA-Class, GLK-Class ("GLC"), ML-Class ("GLE"), GL-Class ("GLS"), CLA-Class, CLS-Class, Vito (and Viano), although certain right-hand-drive models are not available due to the position of the steering column. These later systems include engine and automatic stability controls. ==References== 〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「4Matic」の詳細全文を読む スポンサード リンク
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